<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
</head>
<style>
    div {
        width: 500px !important;
        height: 500px !important;
        /* min-width:1000px; */
        transition: all 1s ease;
    }
</style>

<body>
    <div id="app">

        <div v-bind:style="{color:a1,background:a2}">
                    内部
        </div>
    </div>


    <script>
      
        var app = new Vue({
            el: '#app',
            data: {
                message: 'Hello Vue22222!',
                a1:'green',
                a2:'red'
            }
        })

        console.log('app', app)
           setTimeout(()=>{
            app.$data.a1 = 'black'
            app.$data.a2 = 'orange'
        },2000)


    </script>
</body>

</html>